Stoker pusher rod



July 1, 1941. c. E. GINGHER STOKER PUSHER ROD I Filed July 15, 1939 2 Sheets-Sheet l Inventor ('arz E 'z'ryker B; @Mm

4 itorneys July 1, 1941.- c. E. GIN' HER 2,247,726

STOKER PUSHER ROD Filed July 15, 1939 2 heets-She et 2 I Inventor cw E 2 22 2 Egg 1% i M Patented July 1, 1941 UNITED STATES PATENT OFFICE 2,247,726 i STOKER PUSHER ROD Carl E. Gingher, Scranton, Pa.

Application July 15, 1939, Serial No. 284,158

gel. 198-221) 20 Claims.

My invention relates generally to means for mechanically moving solid fuel, ashes, and other similar materials through a charging or delivering tube, and particularly to automatic stoker pusher rods of the self-centering type, and an important object of my invention is to provide efficient and relatively inexpensive pusher rods of this character which can be readily adapted to different forms of automatic coal stokers and the like.

Another important object of my invention is to provide pusher rods of the character indicated which because of their form and relatively lighter weight and smaller surfaces in frictional contact with surrounding mechanismi, require less power for operation and positively act to center themselves in the coal tube or the like, and which produce more uniform and effortless distribution of the fuel to the firepot, while positively avoidiriig packing and clogging of the coal tube or the li e.

Other important objects of my invention will be apparent from a reading of the following de, scription taken in connection with the drawings, wherein for purposes of illustration I have shown the preferred embodiment of my invention.

In the drawings: 7

Figure 1 is a longitudinal sectional View taken through an automatic stoker of generally conventional form and showing an arrangement of one embodiment of the invention therein;

Figure 2 is a side elevational view of this embodiment of pusher rod;

Figure 3 is a transverse vertical sectional view taken through Figure 2 approximately on the line 33;

Figure 4 is a longitudinal sectional view taken through a slightly modified form of automatic stoker and showing a further embodiment of the push rod of the present invention;

Figure 5 is an elevational view of the axially outward end of the second-mentioned push rod;

Figure 6 is a transverse vertical sectional view taken through Figure 4 approximately on the line 6-6 and looking toward the left in the direction of the arrows.

Referring in detail to the drawings and particularly to Figures 1, 2 and 3 thereof, the numeral 5 generally designates a conventional form of coal hopper which empties into the rear end of the coal tube 6 whose opposite end is gradually curved as indicated by the numeral 1 into the firepot which is generally designated 8. The

pusher ,rod embodiment shown in these figures is generally designated 9 and works in the coal tube 6 and is pushed back and forth by a link arrangement Ill which is operated by 2. connect ing rod H in turn operated by a motor l2 which also operates the blower l3, the blower having 5 a conduit 14 which is in communication with the coal tube 6 via the opening l5. The link arrangement l0 also operates the ash moving rod' I6 which works in the ash tube 'l'! which is situated below the coal tube 6.

one end with a tapered extension [8 which terminates in a small diameter rod portion [9 which is attached to the link arrangement already alluded to,-whereby the pusher rod 9 is worked back and forth in the coal tube 6. The axially outward end of the pusher rod 9 is square out as indicated by the numeral 20, and the pusher rod further has a relatively short smooth portion 2l which has its axially inward end defined by the right triangular cross section groove 23 which runs to the axially inward end 'of the tapered portion [8, continuously, thereby defining a but'' tress screw thread on the rod. The smooth pertion 2| extends to and forms the axially outward end of vthe pusher rod. j

The depth of the spiral right triangular cross section groove 23 increases with uniform gradual tion from the tapered portion ill to the smooth portion 2!. The depth of this spiralgroove 23 increases toward the axially outward or retort end .of the pusher rod and decreases in" depth toward the opposite or axially inward end of the pusherrod, I The formation of the groove 23 presents a right angular face of thebuttress thread directly toward the retort or discharge end thereof and the other and beveled face leans toward the hopper or feed end of the coal tube. This right angular face is generally designated 24, and the] acutely angula/ted' face is generally designated 25. w I l g The continuous right angular face of the pusher rod thread acts to move coal in an axially out-- ward direction toward the retort at each and every point along the entire coal passagewhen the pusher rod is reciprocated in the coal vtube as already indicated. This arrangement keeps the entire supply of fuel moving outwardly to-- ward the retort in a single column.

The length of the stroke 'of the pusher rod 9' can be varied to suit and still leave a' right angular face at each point along its entire length, active to move fuel.

The length of the stroke required to move a given amount of fuel is cut down considerably by the present improvement in a pusher rod, by the provision therein of the continuous right angular face rather than the spaced lugs and projecting faces or right angular faces which are out like notches at different distances from one another, in other forms of pusher rods. The reduced stroke length affords a greater leverage and reduces the power required, so that power necessary to properly actuate other types is saved and expenses of operation and wear and tear on the machinery correspondingly reduced.

The gradual and uniform increase in the depth of the spiral groove 23 accomplishes a twofold purpose. The increasing depth provides more of the right angular face of the thread to engage with the fuel. The greater depth of the groove also decreases the cross sectional area of the pusher rod and provides correspondingly more space for the fuel to expand and loosen so that it is prevented from packing and crushing. On the back stroke of the pusher rod the acutely angulated face of the thread eliminates the undesirable wedging in the inside of the coal tube which is an unavoidable consequence of employing other types of pusher rods which have uniform depth grooves. The combined increase in fuel pushing surfaces as the distance from the hopper increases and the decrease in the cross section in a direction away from the hopper, enables the pusher rod 9 to relieve itself of any wedging on the back stroke and this eliminates the necessity for a large portion of the power required by other types of pusher rods which have no relief of this character on the back stroke but instead wedge the fuel aside, and therefore require correspondingly more power for their operation, besides subjecting the parts to greater wear and tear.

The balanced and equalized strain on all sides of the pusher rod 9 on the forward stroke which comes naturally from its form, eliminates the necessity of having the pusher rod contact the bottom of the coal passage, and enables it to operate without a support at its axially outward end, and to work in a direct forward thrust. The pressure relieving action provided for by the means already described, and the beveled face of the groove being equal on all sides of the pusher rod, enables the pusher rod to center itself exactly in line upon the backward pull, so that when flexibly coupled to the driving mechanism at the hopper end of the coal tube, the pusher rod 9 acts as a self-centering floating pusher rod.

The outer end of the pusher rod at the terminal of the head 2| being the full diameter of the pusher rod, and being disposed to extend from the fuel passage 6 into the bottom of the retort 8 where the elbow or incline I is located and where there is no confining of the fuel to cause wedging asv would be the case in the fuel passage, this head acts to thrust more fuel than the fuel engaging surfaces move, due to its diameter and the result is that the fire bed is lifted upwardly on each forward stroke of the pusher rod. The fire bed having in this manner been moved, provides place for more fuel brought forward by the pusher rod. On the back stroke the fire bed is dropped again to its original position upon that amount of fuel which was moved forward in the manner indicated. This action creates a constant slight agitation of the fire bed thereby reducing the formation of clinker masses and producing a loose fire bed favoring a free passage of air up through the fire bed as well as a more even and uniform distribution of air therethrough, and the added air action of the slight agitation constantly changes the air passages around the particles of fuel, with obvious combustion advantages. All of these desirable things are accomplished without separating one particle of fuel from those surrounding it and without any plowing through or violent disturbance of the fuel or of the fire bed as is consequent upon the employment of a fin or additional pusher projecting from the pusher rod, as is to be found in the prior practice.

While steel, iron, and bronze have been used for the construction of pusher rods, the natural weight thereof produces an overhanging strain where attempts are made to support the rods from one end, so that these could not when flexibly coupled, find and maintain their own center in the charge in a coal tube, since their own weight would bear them down. While I have utilized and experimented with many types of materials, it appears that I am the first to utilize aluminum and aluminum alloys for constructing a pusher rod to eliminate the strains caused by the weight of the rod itself, and to enable making a floating or a solidly coupled pusher rod which does not need to beoversize in cross section or in bulk to be strong enough to support its own weight when supported at one end only. The production of the self-centering and self-supporting pusher rod enables important savings in the size of coal passages required to accommodate the same and provides more fuel space for fuel in the coal tubesof old style stokers.

The reciprocating movement of the pusher rod provided with the continuous shoulder produces little or no friction on the vertical faces thereof and the rod can be rotated back and forth on its axis soas to rotate the required amount through any suitable adjustment of the driving mechanism, such as a part of a revolution, in one direction to move the amount of fuel desired. As the pusher rod is rotated in the opposite direction it permits the fuel to. slide by the beveled face and unpack, and this is a desirable effect which cannot be accomplished with the use of an ordinary worm drive. All of the advantages are claimed for the present invention of the reciprocating end motion for this reciprocating revolving motion. This reciprocating drive of my pusher rod eliminates the ratchet wheels, ratchet dogs, shear pins, and clogging that are incident to the ordinary worm drive types. My pusher rod creates tremendous power through a positive crank arm drive which moves the pusher only a fraction of a revolution in either direction.

Another important feature of the present invention is its capability of being attached to the center of a fiat faced plunger in such a way that the face of the plunger still regulates the amount of fuel moved forwardly or axially outwardly from the hopper, and at the same time avoids the tendency to take additional coal from the hopper. This is accomplished by terminating the spiral groove at a point which is short of being extended into the bottom of the supply hopper,

while the diameter thereof can be left at that of the full outside diameter of the plunger rod. This avoids any pulling back of the fuel, and the plunger rod being smooth at the point under the hopper, has no positive action on the fuel at the projecting position,-the fiat faced plunger 26 to which it is attached is provided with the mem hopper. The plain rod portion immediatelyadjacent the coal hopper (but not in the coal passage) can be smaller in diameter and a slight point under the hopper it would tend to move the fuel in the same manner it would do if used by itself and without a flat faced plunger. Struc ture to carry out the arrangements discussed immediately above are shown in Figures 4, 'and 6 of the drawings, setting forth a concrete embodiment of the invention differentfrom that described in connection with Figures 1, 2 and 3.

The pusher rod which is generally designated 9a. in Figures 4, 5 and 6 of the drawings, has an elongated smooth reduced portion I911; corresponding to the reduced portion l9 in the first described embodiment, and on this reduced portion is mounted the three-quarter circular fiat-faced plunger 25 which works in a conforming opening I541, corresponding in position to the opening l5 as clearly shown in Figure 4 of the drawings. This fiat face plunger 26 rides close to the bottom of the coal tube and in a position to force the fuel coming from the hopper 511. into the small end of the coal tube and into the sphere of action of the grooved portion of the pusher rod 9a. Operating mechanism generally designated Illa similar to that advocated in the first described embodiment of the invention is connected to' the plunger 25 as indicated by the numeral 21, to operate the pusher rod which in this instance includes the plunger 26. v

The axially outward end of the pusherrod presently described embodiment of the invention is provided with a smooth generally conical head 2 la which is longer and. of greater relative diameter than the head 21 and has on the top thereof in a position corresponding to the fiat top 28 where the coal tube is of the tapered type and the action of the fuel moves the rod upwardly out of j the alignment on the back stroke. When this form of pusher rod is utilized on a stoker" equipped with the said tapered coal passa drand a fiat faced plunger 26 is used to lighten the load of lifting the fuel at the elbow 1a, the rod ea is attached to the center of the flat faced plunger 26 and is equipped with the larger fiat faced head 2 la at the retort end to do the lifting or' pushing of the coal up along the elbow la. This larger head 2la is tapered up from the diameter of "the plunger rod and because of this increased diameter, the coal under this tapered section'would:

unless the member 29 were provided,tend totoo greatly elevate the pusher rod on the back stroke.

In more precise language the passage inay be said to flare toward the retort" rather than't'o taper and in this sense the word "taper is 'used' herein.

The cross sectional area of the face of the head Zlc on the retort endis made approximately equal to the cross sectional area or work ing face of the fiat faced plunger 26 to which the rod 9a is attached as already indicated. "In order to keep the rod So from turning and so' that the projection 29 maintains its upwardly However, should the spiral groove This projection 29 is arranged to engage and slide against the top of the coal tube;-

f Although I have shown and described herein tioned flat top 28 on its top or at one side, and this flat faced plunger works through a correspondingly shaped opening l5a, thereby preventing'both the plunger and the rod from revolving.

preferred embodiments of my invention, it is to be definitely understood that I do not desireto limit the application of the invention thereto, and any change or changes may be made in the structure and arrangement of the parts, within the spirit of the invention and the scope of th subjo-ined claims.

- What I claim is:

1. A coal tube pusher rod of the reciprocating type, said pusher rod comprising a bar formed with a spiral groove in its surface and running around the bar for a major portion of the length of the bar and defining a buttress thread, said spiral groove increasing in depth from the feed endof the bar toward the firepot end of the rod,-

in combination with a coal tube containing coal,

said groove acting on the coal in a manner to center said pusher rod with respect to the line of pull on the rod during reciprocation thereof in the coal tube.

2. A coal tube pusher rod of the reciprocating type, said pusher rod comprising a bar formed with a spiral groove in its surface and running around the bar for a major portion of the length of the bar and defining a buttress thread, said spiral groove increasing in depth from the feed: end of the bar toward the firepot end of the rod,

the axially outward end of said .bar being formed with a head having an axially outwardly facing flat face.

3. A coal tube pusher rod of thereciprocating type, said pusher rod comprising a bar formed with a spiral groove in its surface and running aroundthe bar for a major portion of the'length,

of the bar and defining va buttress thread, said spiral groove increasing in depth from the feed end of the bar to the firepot end of the rod,'and a hopper coal moving plunger fixed on the axially inward end of said rod and having an axially outwardly facing flat face, said plunger being'of substantially larger cross section than the said rod.

" 4. In combination, a coal tube, a longitudinally formed in the surface of said rod, said spiral buttress thread increasing in depth toward the firepot end of said coal tube.

6. In combination, a coal tube, a longitudinallyreciprocable pusher rod in said coal tube, thediameter of the rod being considerably less than, that of the coal tube, and a spiral buttress thread formed in the surface of said rod, anda head on the firepot end of said rod having a flat face fac ing'the firepot end of the coal tube.

'7. In combination, a coal tube, a longitudi-- nally reciprccable pusher rod in said coal tube, the diameter of the rod being considerably .less

than that of thecoal tube, and a spiral buttress thread formed in the surface of said rod, and a head on the firepot end of said rod-having a flat face facing the firepot end of the coal tube, said tapered on its underside so as to ride supportably upon the coal thereunder in the coal tube.

8. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube, the diameter of the rod being considerably less than that of the coal tube, and a spiral buttress thread formed in the surface of said rod, and a headon the firepot end of said rod having a flat face facing the firepot end of the coal tube, said head being larger in diameter than said rod and tapered on its underside so as to ride supportably upon the coal thereunder in the coal tube, and a vertical projection on said head positioned to bear against the top of the coal tube to prevent said rod from being forced upwardly from normal position.

9. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube, the diameter of said rod being considerably less than that of the coal tube, coal pushing means on the surface of said rod, said rod having a reduced shank at the hopper end of the rod, a coal feeding plunger fixed on the terminal of said reduced shank, the cross section of said plunger being considerably larger than that of said reduced shank, and means mounting said plunger relative to said coal tube, a head on the end of said rod opposite said shank, said head having a fiat face facing the firepot end of said coal tube, said head having a lateral projection arranged to slide against a Wall of the coal tube, the bottom of said head being tapered to bear on the coal below said head for lifting effect on the rod on the back-stroke of the rod.

10. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube, the diameter of said rod being considerably less than that of the coal tube, coal pushing means on the surface of said rod, said rod having a reduced shank at the hopper end 'ofthe rod, a coal feeding plunger fixed on the terminal of said reduced shank, the cross section of said plunger being considerably larger than that of said'reduced shank, and means mounting said plunger relative to said coal tube, a head on the end of said rod opposite said shank, said head having a fiat face facing the firepot end of said coal tube, said head having a lateral projection arranged to slide against a wall of the coal tube, the bottom of said head being tapered to bear on the coal below said head for lifting effect on the rod on the backstroke of the rod, said lateral projection being arranged to' engage the top of the coal tube to prevent the rod from being forced upwardly out of position onthe backstroke of the rod.

11. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube,

the diameter of said rod being considerably "less than that of the coal tube, coal pushing means on the surface of said rod, said rod having a reduced shank at the hopper end of the rod, a coal feeding plunger fixed on the terminal of said reduced shank, the cross section of said plunger being considerably larger than that of said reduced shank, and means mounting said plunger relative to said coal tube, said coal pushing means comprising a spiral buttress thread formed on the surface of said rod.

12. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube, the diameter of said rod being considerably less than that of the coal tube, coal pushing means on the surface of said rod, said rod having a re head being larger in diameter than said rod and duced shank at the hopper end of the rod, a coal feedingplunger fixed on the terminal of said reduced shank, the cross section of said plunger being considerably larger than that of said reduced shank, and means mounting said plunger relative'to said coal tube, said means including means preventing rotation of said plunger, said coal pushing means comprising a spiral buttress thread formedon the surface of the rod.

13. In combination, a coal tube, a longitudinallyreciprocable pusher rod in said coal tube, the diameter of said rod being considerably less than that of the coal tube, coal pushing means on thesurface of said rod, said rod having a reduced shank at the hop-per end of the rod, a coal feed ing plunger fixed on the terminal of said reduced shank, the cross section of said plunger being considerably larger than that of said reduced shank, and means-mounting said plunger relative to said coal tube, a head on the end of said rod opposite said shank, said head having a fiat face facing the firepot end of said coal tube, said head having a lateral projection arranged to slide against a wall of the coal tube, the bottom of said head being tapered to bear on the coal below said head for lifting effect on the rod on the backstroke of the rod, said lateral projection being arranged to engage the top of the coal tube to prevent the rod from being forced upwardly out of position on the backstroke of the rod, said coal pushing means comprising a spiral buttress thread formed on the surface of the rod.

14. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube, the diameter of the rod being considerably less than that of the coal tube, and a spiral buttress thread formed in the surface of said rod, said buttress thread having one face facing directly toward the firepot end of said coal tube, the interior of said coal tube being tapered toward the firepot end of the coal tube.

1.5. In combination a coal tube, a longitudinally reciprocable pusher rod in the coal tube and extending along the rod a central body of buttress pusher means having faces adapted to push coal forward through the tube and having rearward faces sloping inwardly toward the center'of the rod to minimize backward drag of the coal, the central body of buttress means as a whole helically surrounding the rod, the rod and buttress means as a whole being spaced substantially from all the surrounding walls of the coal tube.

16..In combination a coal tube, a longitudinally reciprocable pusher rod in the coal tube and extending along the rod a central body of buttress pusher means having faces adapted to push coal forward through the tube and having rearward faces sloping inwardly toward the center of the rod to minimize backward drag of the coal, the central body of buttress means as a whole surrounding the rod, the rod and central body; of buttress means as a whole being spaced substantially from all the surrounding walls of the coal tube, and a spacer element carried at the upper'side of the rod to prevent pushing of the rod and buttress means against the upper walls of the coal tube.

1'7. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube and a central body of pusher means having buttress faces adapted to push coal forward through the tube the pusher means as a whole arranged helically around the rod, and spaced from all the surrounding walls of the coal tube.

18. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube and a succession of pusher elements having buttress faces adapted to push coal forward through the tube and as a whole arranged helically around the tube, and being spaced from all the surrounding walls of the coal tube, the depth of the buttress faces as a whole gradually deepening toward the forward end of the coal tube.

19. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube and a series of buttress pusher elements formed on the rod and generally arranged as a helical thread and as a whole being spaced from all surrounding walls of the coal tube, and a head on the forward end of the rod extending upwardly to serve as a spacer from the upper walls of the coal tube.

20. In combination, a coal tube, a longitudinally reciprocable pusher rod in said coal tube and a series of buttress pusher elements formed on the rod and generally arranged as a helical thread 10 increasing in feeding power forwardly.

CARL E. GINGHER. 

